Cabinet allies of Gordon Brown insisted there was no plausible alternative to the prime minister today, as they condemned attempts by backbench Labour MPs to force a leadership contest.

John Denham, the universities secretary, said he would not be part of a plot to remove Brown.

"This campaign by a handful of MPs is prepared to destabilise and disrupt the positive Labour message. They seem to think the threat of making Labour unelectable for years will make people like me get rid of Gordon," he told the London Evening Standard.

"Suppose we did. Do they have a candidate? Not as far as any of us can see. Do they have a more convincing explanation of Britain's fundamental problems? Not that I have heard."

The MPs were indulging in "the politics of despair and destruction".

Douglas Alexander, the international development secretary, said it was "unconvincing" for some MPs to suggest there was "significant support" for an alternative.

"I think the support for Gordon stretches across the party … My sense is that the party, like the country, wants the government to be getting on with the real challenges given the kind of financial difficulties that the world economy is facing, that we've heard about with Lehman Brothers today," he said.

"I think the right course for both individual members of the government and individual members of the party is to be focusing on real challenges that the country faces and looking ahead to our conference next week."

Siobhain McDonagh, an assistant whip, and Joan Ryan, Labour's vice-chair, were removed from their posts after requesting leadership nomination papers to trigger a challenge to Brown. Senior cabinet ministers past and present told the Guardian they had been taken by surprise by the grassroots revolt.

Today another former minister, Rossendale and Darwen MP Janet Anderson, confirmed she had asked for nomination papers to be sent out.

Writing in the Evening Standard, Anderson said: "What is clear is that we have to do something. We cannot go on 'sleepwalking into oblivion', but we are - and we will continue to do so if we do nothing to address the reasons why we have been so far behind in the polls.

"That means a root-and-branch review of our policies and how we communicate them to the voters. And if that requires a change of leadership, so be it."

Senior cabinet ministers past and present told the Guardian they had been taken by surprise by the grassroots revolt.

The prime minister's spokesman confirmed this morning that Barry Gardiner, the Brent North MP who was one of those calling for a leadership contest at the weekend, was no longer Brown's special representative on forestry matters, as theguardian.com revealed yesterday.

Gardiner wrote in the Sunday Times: "The public has stopped listening to Gordon Brown. He is not a popular prime minister, but he would continue to have my support if he showed sound judgment, international leadership and political vision.

"Instead we have vacillation, loss of international credibility and timorous political manoeuvres that the public cannot understand."

Brown is due to attend a meeting of Labour's national executive committee tomorrow where they will discuss - but are likely to reject - calls for leadership nomination papers to be sent out.

Ray Collins, Labour's general secretary, has refused to distribute nomination papers, in keeping with the convention of the last 11 years that they are only sent out to individual MPs upon request.

With some cabinet ministers coming under pressure to break ranks, Brown also faces a potentially hazardous political cabinet meeting tomorrow.